diff --git a/sjrpc/core/rpcconnection.py b/sjrpc/core/rpcconnection.py
index 4b0187cd9e7f965f929bdbf959ad626422c13d96..b1466560c6750dd4f7545031ce91a767c8485cca 100644
--- a/sjrpc/core/rpcconnection.py
+++ b/sjrpc/core/rpcconnection.py
@@ -55,6 +55,9 @@ class RpcConnection(object):
         # The manager of this connection 
         self._manager = manager
 
+        # Is the RpcConnection connected to its peer:
+        self._connected = True
+
     @classmethod
     def from_addr(cls, addr, port, manager, enable_ssl=False, timeout=30.0,
                   cert=None, handler=None):
@@ -163,6 +166,9 @@ class RpcConnection(object):
            Message must be a jsonisable structure.
         '''
 
+        if not self._connected:
+            raise RpcError('SendError', 'disconnected from the peer')
+
         logging.debug('Sending: %s', message)
         json_msg = json.dumps(message)
         size = struct.pack('!L', len(json_msg))
@@ -373,6 +379,8 @@ class RpcConnection(object):
         :type callback: :class:`str` or callable or None
         '''
 
+        self._connected = False
+
         try:
             self._sock.close()
         except socket.error as err: